1. Field of the Invention
The invention relates to a manifold for an engine and more particularly to a multiport manifold for a multicylinder engine.
2. Description of the Prior Art
Multicylinder engines are used in a variety of devices, such as motorized vehicles including motorcycles.
Two cylinder motorcycle engines, such as those commonly used on a Harley Davidson motorcycle are arranged in a V configuration in which the two cylinders are in line longitudinally on the motorcycle but are set at an angle such that a forward cylinder is angled slightly forwardly and a rear cylinder is angled slightly rearwardly to form a V shape when viewed from the side. The intake ports for the cylinders are located adjacent to one another at the inside of the V. Generally a single carburetor is provided since the cylinders fire alternatively and a single manifold connects the carburetor to the two inlet ports, the manifold having one port at a first connected to the carburetor and two ports at the second end one connected to each of the inlet ports.
Such a construction has disadvantages in that during an intake stroke, the air-fuel mixture is drawn toward one of the outlet ports of the manifold and, therefore away from the other port. When the first intake port closes and the opposing intake port opens, some time is needed for the air-fuel mixture to move from the now closed port to the now open port.
In some instances, it is desirable to utilize two separate carburetors, one for each cylinder, but because of the tight space requirements it is very difficult to arrange manifolds from the separate carburetors to the separate cylinders without excessive bending and constricting of the manifold passages. Also, because of the space constriction manifolds which have been used in the past to supply the air-fuel mixture to the cylinders have been different in configuration for the front cylinder and rear cylinder thus having a detrimental effect on performance.